Sometimes you don't have to have words to explain how amazing God's creation is. Satellite Images, all from the same time frame on October 24th of a well-developed Low Pressure offshore of the Pacific Northwest Coast. Enjoy.
-Meteorologist Dan Schreiber
The above radar loop shows a thunderstorm that produced one-half-inch diameter hail and an EF-2 tornado in Manzanita, Oregon, on Friday...leading to several reports of structural damage to houses and buildings and prompting a state of emergency.
Before I go any further, I will quickly elaborate on Tornadoes versus Funnel Clouds versus Waterspouts.
Funnel Clouds: Tornadoes that do not touch the ground.
Waterspouts: Tornadoes over water. If the waterspout continues on land, it becomes a tornado.
Tornadoes: Originate as Funnel Clouds, and sometimes as Water Spouts.
I'll break the Manzanita Tornado down below
A thunderstorm capable of producing a waterspout is observed on Portland Weather Radar offshore of Tillamook County at 10AM Pacific Time. A distinct "Hook Echo" is seen this storm, indicating a strong updraft region (on the left), generally near where a tornado would form. On the right, velocity imagery shows intense rotation within the storm (red & green next to each other), and has place a tornadic vortex signature to indicate this storm as capable of producing a tornado.
The severe thunderstorm begins to make landfall, dropping hail the size of pennies. The "hook echo" is well-established, and the storm takes the shape of a supercell thunderstorm. Supercell Thunderstorms are known to be the most violent, and can contain significant rotation capable of producing tornadoes. In this case, velocity imagery shows this rotation very clearly.
The supercell thunderstorm looses a bit of shape, likely because of the impact it has made with the land surface and local terrain. Nonetheless, the strongest rotation is seen within this storm at this time just offshore of the Town of Manzanita, with "gate to gate" (opposing) shear values of roughly 140 knots, indicating enough rotation for an EF-2 Tornado.
Radar 3-D imagery at the time the Manzanita Tornado was reported. Unlike severe thunderstorms and tornadoes through the Central & Eastern United States, which can grow to over 60,000 feet tall and can destroy several towns in a matter of minutes, thunderstorms, waterspouts and tornadoes in the Pacific Northwest don't appear quite as ominous, but can still be very dangerous. Shown in this image is the "core" of the thunderstorm, generally where the largest hail and rain drops can be found.
The key to this storm that struck Manzanita on the 14th of October was the strong wind shear found within. This is evident by a quick sandwich slice of this storm as it made landfall, showing a diagonal stack with height of the red & pink reflectivity values (known as dBZ). When wind shear allows these storms to diagonally align, this allows for strong updrafts & downdrafts within, enabling large hail, strong wind gusts, and even tornadoes.
Meteorologist Dan Schreiber
Smalltown Weather is a Weather Ready Nation Ambassador
It's already widely advertised...and in the wake of Hurricane Matthew in the Atlantic, the first significant seasonal storm is on the horizon for the Pacific Northwest. And it will be powerful...the National Weather Service comparing it to the Columbus Day Storm of 1962...and since I wasn't around back then, I had to look it up...turns out that it brought winds comparable to that of a Category 2, even Category 3, Hurricane. Well, hang on to your britches...this one will be windy (and rainy), but probably not quite as intense.
This storm will come in two waves...one Thursday, the other Saturday. Thursday looks rainier than Saturday, and Saturday looks windier than Thursday. Friday looks to have the best of both worlds.
Let's take a look...
Total Precipitable Water shows the amount of moisture you would get (in inches) if you were to take all of the water in the atmosphere during any given time and squeeze it out until it was completely dry. In most cases, anything over 2 inches is considered extremely high moisture content...and widespread heavy rains should be anticipated. So why does 2 inches of precipitable water create several more inches of rain? Because it usually has a source of moisture that continues to feed it. Just like your garden hose only holds a little bit of water inside it (i.e. it's precipitable water), it has a source to the water pipes, and if left on, can flood your garden.
In conclusion, it will be a storm that folks will remember. Panic, no...but be prepared and stay off the roads if possible, and definitely the ocean, beaches & low-lying areas. Heavy rain, high tides, and dangerously strong winds are a bad combination...likely leading to mud slides, downed trees, sinkholes, powerful sneaker waves, damaged & inoperable power lines...even structural damage.
As always, your authoritative weather source is the National Weather Service, and they are responsible for issuing any and all weather warnings, watches, and advisories, both out in the ocean and on land:
Meteorologist Dan Schreiber
Ever since the February 22nd, 2016 hail storm in Del Rio, Texas, in which one of my trucks was spontaneously morphed into a block of aged Swiss cheese, I've been a little more cautious about where I park my vehicles when we're expecting some bad weather.
I think the neighbors have caught on too...late nights when I randomly move my truck up on the lawn and park it under my pecan tree, the neighborhood starts coming out, one-by-one, moving their vehicles into strange places hoping to protect them from the next hail storm. One of my employees just drives his to the car-wash garage and waits out the storm. I guess if the weatherman does it, then he must know something.
While the fall season in Del Rio isn't nearly as active, atmospherically speaking, as the springtime, it certainly brings an increased chance of another hail storm. The hot summer months make the region too warm for hail, and the jet stream, which generally fuels dangerous storm outbreaks, is pushed much further north. But during the fall, winter sits on the horizon as the jet stream creeps further south and replaces the hot, humid temperatures of the summer with cool, crisp air from the north. The interaction between these two masses of air is what aids in the development of dangerous storms...which require cool air aloft and warm air near the earth's surface.
There's usually a dangerous storm or two during the fall season through South-Central Texas. Heavy rain and flooding is the most deadly of these storms, looking back through historical records, and we've already had a couple of these the past few months. But yes, a hail storm - even a tornado - may be spotted on the Laughlin Air Force Base radar screen in and around the Del Rio & Acuña area this season.
If we're fortunate, I won't be parking my truck under any pecan tree this season, I'll reserve that for the springtime.
- Dan, the Weatherman